(x) The differentiation of secx with respect to x is `secxtanx`

Explanation

We will differentiate the given function using first priciple.

Here, `f(x) = secx`

`:. f'(x) = Lim_(h->0) (f(x+h) - f(x))/h`

`= Lim_(h->0) (sec(x+h) - secx)/h`


`= Lim_(h->0) (1/(cos(x+h)) - 1/cosx)/h`

`= Lim_(h->0) (cosx - cos(x+h))/(hcosxcos(x+h))`

`= Lim_(h->0) (-2sin((x+x+h)/2)sin((x-x-h)/2))/(hcosxcos(x+h))`

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